JP7283085B2 - travel control device - Google Patents

Description

The present invention relates to a travel control device.

BACKGROUND ART As a conventional travel control device, for example, a technique such as that described in Patent Document 1 is known. The travel control device described in Patent Document 1 includes a laser distance sensor that emits a laser beam and detects the reflected light to measure the distance to an object. The current position of the automatic guided vehicle is estimated by matching the measurement data from the laser distance sensor and the map data with the data memory that stores the correspondence information with the coordinates, and the automatic guided vehicle is determined based on the estimation result. and a processing unit for running according to the route data.

JP 2011-253414 A

When estimating the position of a moving object using a laser, as in the above conventional technology, the position estimation accuracy depends on the detection distance performance of the laser distance sensor. Therefore, depending on the surrounding environment in which the mobile body travels, the accuracy of estimating the position of the mobile body is degraded. Specifically, when the object that reflects the laser exists at a position far from the moving body, the position estimation accuracy of the moving body is lower than when the object exists at a position closer to the moving body.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a travel control device capable of improving the accuracy of estimating the position of a moving object in a place where the accuracy of estimating the position of the moving object is required.

One aspect of the present invention is a travel control device that automatically travels a mobile object along a travel route. and a control unit for controlling a driving unit of the moving object so that the moving object travels along the travel route, and the position estimation unit irradiates a laser around the moving object and receives reflected light of the laser. a distance detection unit for detecting a distance to an object around the moving body; changes the usable distance range of the detection data of the distance detection unit in accordance with the traveling place of the mobile body, and performs an estimation calculation of the position of the mobile body.

In such a travel control device, the distance detection unit irradiates the surroundings of the moving object with a laser beam to detect the distance to objects around the moving object. Calculation for estimating the position of the moving body is performed based on The estimation calculation unit changes the usable distance range of the detection data of the distance detection unit according to the traveling location of the mobile object, and performs an estimation calculation of the position of the mobile object. Here, an object that reflects the laser exists in a place where position estimation accuracy is required. When the moving object travels in a place where position estimation accuracy is required, by shortening the use distance range of the detection data of the distance detection unit, in a place where position estimation accuracy of the moving object is required, Since the position is estimated using features located near the moving object, it is possible to improve the accuracy of estimating the position of the moving object.

The travel control device further comprises a determination unit for determining whether the moving object travels in a place where accuracy of position estimation is required, based on the position of the moving object estimated by the position estimation unit, and an estimation operation. The unit uses the detection data of the distance detection unit more when the determination unit determines that the moving object travels in a place where accuracy is required compared to when the determination unit determines that the moving object travels in a place other than the location where accuracy is required. The distance range may be shortened and the position estimation calculation of the moving body may be performed. With such a configuration, when the mobile body travels in a place requiring accuracy, the range of distances in which the detection data of the distance detection unit can be used is shortened, so the accuracy of estimating the position of the mobile body is improved.

The moving body may have a cargo handling device that performs cargo handling work, and the location requiring accuracy may be in front of a cargo handling station where cargo handling is performed by the cargo handling device. In such a configuration, since the position of the moving body can be estimated with high accuracy before the cargo handling station where cargo handling is performed by the cargo handling device, the moving body can be accurately stopped at the cargo handling station.

Advantageous Effects of Invention According to the present invention, it is possible to improve the accuracy of estimating the position of a moving object in a place where the accuracy of estimating the position of the moving object is required.

1 is a schematic configuration diagram showing a cruise control system including a cruise control device according to an embodiment of the present invention; FIG. 2 is a block diagram showing the configuration of a travel control device shown in FIG. 1; FIG. 3 is a flow chart showing details of an arithmetic processing procedure executed by the SLAM controller shown in FIG. 2; 3 is a conceptual diagram showing a normal range and a short range of detection data of a laser sensor set in the SLAM controller shown in FIG. 2; FIG. FIG. 3 is a flow chart showing details of a determination processing procedure executed by a usage distance change determination unit shown in FIG. 2; FIG. 3 is a flowchart showing details of a control processing procedure executed by a drive control unit shown in FIG. 2;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a cruise control system provided with a cruise control device according to one embodiment of the present invention. In FIG. 1, a travel control system 1 is a system that allows a mobile object 2 to travel unmanned from a start point 3A to a destination point 3B.

The moving body 2 is, for example, a battery-powered forklift. A front part of the moving body 2 is equipped with a cargo handling device 2a for carrying out cargo handling work. It should be noted that the traveling direction of the moving body 2 may be forward or backward.

The travel control system 1 includes a travel control device 4 that automatically travels the mobile object 2 along a virtual guide line 3 that is a travel route from a start point 3A to a destination point 3B, and a magnetic mark 5 with associated driving instruction data.

The virtual guide line 3 is a travel route virtually set on the data. In addition, although the virtual guide line 3 is a straight path in FIG. 1, it may be a curved path. The positions of the virtual guide line 3 including the start point 3A and the destination point 3B are represented by two-dimensional coordinates (XY coordinates). Here, the two-dimensional coordinates of the starting point 3A are (0, 0). The two-dimensional coordinates of the destination point 3B are (100, 0). The magnetic mark 5 is installed on the floor. The magnetic marks 5 are embedded at positions corresponding to the sides of the virtual guide line 3 on the floor surface.

FIG. 2 is a block diagram showing the configuration of the travel control device 4. As shown in FIG. In FIG. 2, the traveling control device 4 of this embodiment is mounted on the moving body 2. As shown in FIG. The travel control device 4 includes a position estimation unit 6 , a magnetic mark sensor 7 and an automatic travel control unit 8 .

A position estimation unit 6 estimates the position of the mobile 2 . The position estimation unit 6 estimates the self-position of the mobile body 2 using, for example, SLAM (simultaneous localization and mapping) techniques. SLAM is a self-localization technique that uses sensor data and map data to estimate self-localization. SLAM uses a laser range scanner or the like to simultaneously estimate its own position and create an environment map. The position estimation unit 6 has a laser sensor 9 and a SLAM controller 10 .

The laser sensor 9 is a distance detection unit that detects the distance to objects around the moving body 2 by irradiating the surroundings of the moving body 2 with a laser and receiving the reflected light of the laser. As the laser sensor 9, for example, a laser range finder is used. The laser used may be a 2D laser or a 3D laser.

The laser sensor 9 irradiates a laser in a fan shape (see FIG. 4). Specifically, the laser sensor 9 irradiates a laser within a predetermined angular range (here, 270 degrees) centered on the direction directly behind the moving body 2 . The laser beam emitted from the laser sensor 9 strikes a stationary object, and the laser beam (reflected light) reflected by the stationary object is received by the laser sensor 9 . A stationary object is a wall, a pillar, or the like. Here, the stationary object detected by the laser sensor 9 and used for self-position estimation is assumed to be the feature 30 (see FIG. 4).

The SLAM controller 10 is composed of a CPU, a RAM, a ROM, an input/output interface, and the like. The SLAM controller 10 is an estimation calculation unit that performs an estimation calculation of the position of the moving body 2 based on the detection data of the laser sensor 9 . The position of the moving body 2 is represented by two-dimensional coordinates (XY coordinates) and orientation.

The SLAM controller 10 matches the distance data to the feature 30 detected by the laser sensor 9 with the map data of the surrounding environment of the moving body 2 to perform an estimation calculation of the position of the moving body 2 . At this time, the SLAM controller 10 changes the usable distance range of the detection data of the laser sensor 9 according to the traveling location of the mobile body 2 and performs estimation calculation of the position of the mobile body 2 .

Here, the destination point 3B is a cargo handling station where cargo handling is performed by the cargo handling device 2a of the moving body 2. FIG. A loading station is a place where a forklift is loaded or where the loaded forklift is placed, such as a shelf. Also, at the cargo handling station, a characteristic object such as a pillar of the shelf exists in the vicinity of the forklift.

FIG. 3 is a flow chart showing the details of the arithmetic processing procedure executed by the SLAM controller 10. As shown in FIG. This process is executed when the moving body 2 starts traveling from the start point 3A to the destination point 3B.

In FIG. 3, the SLAM controller 10 first acquires detection data from the laser sensor 9 (step S101). Subsequently, the SLAM controller 10 determines whether or not a short-distance use instruction signal (described later) has been input from the automatic cruise control unit 8 (step S102).

When the SLAM controller 10 determines that the short-distance use instruction signal from the automatic travel control unit 8 is not input, it uses the normal distance range P as the distance range of the detection data of the laser sensor 9, position estimation calculation is performed (step S103). Specifically, the SLAM controller 10 matches the distance data to the feature 30 around the moving body 2 in the normal distance range P of the detection data of the laser sensor 9 with the map data of the surrounding environment of the moving body 2. , performs an estimation operation of the position of the moving object 2 . As a result, the estimated position of the moving object 2 is obtained.

As shown in FIG. 4(a), the normal distance range P is used to estimate the position of the moving body 2 when the moving body 2 travels in a place other than a place where the accuracy of position estimation is required. It is the distance range of the detection data of the laser sensor 9 used. The location requiring accuracy is in front of the destination point 3B, which is the cargo handling station here. A laser emitted from the laser sensor 9 hits a feature 30 arranged within the normal distance range P and is reflected.

The normal distance range P is preset. The normal distance range P matches, for example, the laser irradiation range from the laser sensor 9 . In other words, the normal distance range P is the entire range of detection data of the laser sensor 9 . It should be noted that the normal distance range P does not have to match the irradiation range of the laser from the laser sensor 9 .

When the SLAM controller 10 determines in step S102 that the short-distance use instruction signal has been input from the automatic travel control unit 8, it uses the short-distance range Q as the distance range of the detection data of the laser sensor 9, 2 position estimation calculation is performed (step S104). Specifically, the SLAM controller 10 matches the distance data to the feature 30 around the moving body 2 in the short range Q of the detection data of the laser sensor 9 with the map data of the surrounding environment of the moving body 2. , performs an estimation operation of the position of the moving object 2 . As a result, the estimated position of the moving object 2 is obtained.

As shown in FIG. 4B, the short-distance range Q is set when the moving body 2 travels in a place where the accuracy of position estimation is required, that is, when the moving body 2 moves to a place before the destination point 3B. It is the distance range of the detection data of the laser sensor 9 used for the estimation calculation of the position of the moving body 2 when traveling. The short distance range Q is set to be a distance range shorter than the normal distance range P. The short distance range Q is, for example, a distance range that is half or less than the normal distance range P. A laser emitted from the laser sensor 9 strikes a feature 30 located within the short range Q and is reflected.

After step S103 or step S104 is executed, the SLAM controller 10 outputs the estimated position of the moving object 2 to the automatic cruise control unit 8 (step S105), and executes step S101 again.

Returning to FIG. 2 , the magnetic mark sensor 7 is attached to the lower portion of the moving body 2 . A magnetic mark sensor 7 detects the magnetic mark 5 .

The automatic travel control unit 8 performs predetermined processing based on the position of the mobile object 2 estimated by the position estimation unit 6, and automatically travels the mobile object 2 from the start point 3A to the destination point 3B. It controls the motor 11 and the steering motor 12 .

The traveling motor 11 is a motor that rotates traveling wheels (not shown). The steering motor 12 is a motor that rotates steering wheels (not shown). The travel motor 11 and the steering motor 12 constitute a driving section of the moving body 2 .

The automatic travel control unit 8 is composed of a CPU, a RAM, a ROM, an input/output interface, and the like. The automatic travel control unit 8 has a storage section 13 , a deviation amount calculation section 14 , a usage distance change determination section 15 and a drive control section 16 .

The storage unit 13 stores information about the travel of the moving body 2, such as the positions of the virtual guide lines 3 and the magnetic marks 5, travel instruction data, and the like. The positions of the virtual guide line 3 and the magnetic marks 5 are stored as two-dimensional coordinates. Driving instruction data is associated with each magnetic mark 5 as described above. The travel instruction data includes, for example, an acceleration instruction, a stop instruction, a right turn instruction, a left turn instruction, and the like.

Based on the position of the virtual guide line 3 stored in the storage unit 13 and the position of the moving body 2 estimated by the position estimation unit 6, the deviation calculation unit 14 calculates the deviation between the virtual guide line 3 and the moving body 2. Calculate quantity. At this time, the deviation amount calculation unit 14 calculates the deviation amount between the position coordinates of the virtual guide line 3 and the position coordinates of the moving body 2 and the deviation amount between the direction of the virtual guide line 3 and the direction of the moving body 2. .

The use distance change determination unit 15 is a determination unit that determines whether or not the moving body 2 travels in a place where accuracy of position estimation is required based on the position of the moving body 2 estimated by the position estimation unit 6. is. The use distance change determination unit 15 outputs a short-distance use instruction signal to the SLAM controller 10 when it is determined that the moving body 2 travels in a place where accuracy is required. The short-distance use instruction signal is an instruction signal for causing the SLAM controller 10 to use the short-distance range Q as the distance range of the detection data of the laser sensor 9 for estimation calculation of the position of the moving body 2 . Specific processing of the usage distance change determination unit 15 will be described in detail later.

Based on the amount of deviation between the virtual guide line 3 and the moving object 2 calculated by the deviation amount calculating unit 14, the drive control unit 16 controls the traveling motor 11 and the moving object 2 so that the moving object 2 travels along the virtual guide line 3. It controls the steering motor 12 . Further, when the magnetic mark 5 is detected by the magnetic mark sensor 7 , the drive control unit 16 controls the travel motor 11 and the steering motor 12 so that the moving body 2 travels according to the travel instruction data associated with the magnetic mark 5 . to control. Specific processing of the drive control unit 16 will be described in detail later.

In the above, based on the position of the moving body 2 estimated by the position estimation unit 6, the deviation amount calculating part 14 and the drive control part 16 cause the moving body 2 to travel along the virtual guide line 3. and a control unit for controlling the steering motor 12 .

FIG. 5 is a flowchart showing the details of the determination processing procedure executed by the usage distance change determination unit 15. As shown in FIG. This process is also executed when the moving body 2 starts traveling from the start point 3A to the destination point 3B, similarly to the arithmetic process by the SLAM controller 10 .

In FIG. 5, the use distance change determination unit 15 first acquires the estimated position of the moving body 2 obtained by the SLAM controller 10 (step S111). Then, the use distance change determination unit 15 determines whether or not the moving body 2 travels in a place where accuracy of position estimation is required (step S112).

When the use distance change determination unit 15 determines that the moving body 2 does not travel in the location requiring accuracy, that is, when determining that the moving body 2 travels in a location other than the location requiring accuracy, the procedure S111 is executed again. When the use distance change determination unit 15 determines that the moving body 2 travels in the place where accuracy is required, it outputs a short-distance use instruction signal to the SLAM controller 10 (step S113), and executes step S111 again.

FIG. 6 is a flowchart showing the details of the control processing procedure executed by the drive control section 16. As shown in FIG. This process is also executed when the moving body 2 starts traveling from the start point 3A to the destination point 3B, similarly to the arithmetic process by the SLAM controller 10 .

In FIG. 6, the drive control unit 16 first determines whether or not the magnetic mark 5 has been detected by the magnetic mark sensor 7 (step S121). When the drive control unit 16 determines that the magnetic mark 5 has been detected, it acquires the travel instruction data corresponding to the number of the magnetic mark 5 from the storage unit 13 (step S122).

At this time, when the magnetic mark sensor 7 detects the first (number 1) magnetic mark 5 from the start point 3A, the travel instruction data associated with the number 1 magnetic mark 5 is acquired. When the magnetic mark sensor 7 detects the second (second) magnetic mark 5 from the start point 3A, the travel instruction data associated with the second magnetic mark 5 is acquired.

Then, the drive control unit 16 outputs a control signal corresponding to the acquired travel instruction data to the travel motor 11 and the steering motor 12 (step S123). For example, when the acquired travel instruction data is an acceleration instruction, the drive control unit 16 outputs a control signal to the travel motor 11 to increase the rotation speed of the travel motor 11 . As a result, the speed of the moving body 2 is increased.

After step S123 is executed, or when it is determined in step S121 that the magnetic mark 5 is not detected, the drive control unit 16 determines whether the virtual guide line 3 calculated by the shift amount calculation unit 14 and the moving body 2 is acquired (step S124). Then, the drive control unit 16 outputs a control signal to the traveling motor 11 and the steering motor 12 so that the amount of deviation between the virtual guide line 3 and the moving body 2 becomes 0 (step S125). As a result, the position coordinates and orientation of the moving body 2 come closer to the virtual guide line 3 .

Subsequently, the drive control unit 16 determines whether or not the moving body 2 has reached the destination point 3B (step S126). When the drive control unit 16 determines that the moving body 2 has not reached the destination point 3B, the step S121 is executed again. When the drive control unit 16 determines that the moving body 2 has reached the destination point 3B, the process ends.

In the traveling control system 1 configured as described above, when the moving body 2 is traveling, the laser sensor 9 irradiates the surroundings of the moving body 2 with a laser beam, so that the distance to the feature 30 around the moving body 2 is calculated. is detected, and the SLAM controller 10 performs an estimation calculation of the position of the moving body 2 based on the detection data of the laser sensor 9 .

At this time, before the moving object 2 reaches a place in front of the destination point 3B, as shown in FIG. An estimation calculation of the position of the moving body 2 is performed. Therefore, even a feature 30 that is far away from the moving body 2 can be easily captured by the laser emitted from the laser sensor 9 and can be used to estimate the position of the moving body 2 . As a result, the feature objects 30 can be secured easily because the number of the feature objects 30 can be reduced.

When the moving body 2 reaches a place before the destination point 3B, a short distance use instruction signal is sent from the use distance change determination section 15 of the automatic travel control unit 8 to the SLAM controller 10. FIG. Then, as shown in FIG. 4B, the SLAM controller 10 uses the short distance range Q as the distance range of the detection data of the laser sensor 9 to perform an estimation calculation of the position of the moving body 2. FIG. Therefore, since the features 30 close to the mobile body 2 are used for the position estimation calculation of the mobile body 2, the accuracy of the position estimation calculation of the mobile body 2 is improved.

As described above, in this embodiment, the position estimation calculation of the position of the moving body 2 is performed by changing the range of use of the detection data of the laser sensor 9 according to the traveling place of the moving body 2 . Here, in places requiring accuracy where position estimation accuracy is required, features 30 that reflect the laser, such as pillars and walls of shelves, are present. When the moving body 2 travels in a place where accuracy is required, by shortening the use distance range of the detection data of the laser sensor 9, the moving body 2 can be used in a place where the position estimation accuracy of the moving body 2 is required. Since the position is estimated using the feature 30 located nearby, the position estimation accuracy of the moving object 2 can be improved.

In addition, by shortening the usable distance range of the detection data of the laser sensor 9, objects other than the characteristic object 30 existing at a distance from the moving body 2, such as a person or a forklift, are not detected, so self-position estimation is not possible. It is possible to reduce factors that can cause disturbances, and contribute to improving the accuracy of estimating the position of the moving body 2 .

In addition, in the present embodiment, when it is determined that the moving body 2 travels in a place where accuracy is required, the detection data of the laser sensor 9 is greater than when it is determined that the moving body 2 travels in a place other than the place where accuracy is required. is shortened, and the position estimation calculation of the moving body 2 is performed. Therefore, when the moving body 2 travels in a place where accuracy is required, the use distance range of the detection data of the laser sensor 9 is shortened, so the estimation accuracy of the position of the moving body 2 is improved.

In addition, in the present embodiment, the position of the moving body 2 is estimated with high accuracy before the destination point 3B, which is a cargo handling station where cargo is handled by the cargo handling device 2a. can be made

In addition, in this embodiment, when the moving body 2 travels in a place other than the place where accuracy is required, it is not necessary to place the feature 30 for maintaining the position estimation accuracy near the traveling route of the moving body 2. can reduce the number of

In addition, this invention is not limited to the said embodiment. For example, in the above-described embodiment, the automatic travel control unit 8 determines whether or not the moving object 2 travels in a place where accuracy of position estimation is required. The SLAM controller 10 may determine whether or not the vehicle 2 travels in a location requiring precision, or a host system or the like may determine.

In the above-described embodiment, the cargo handling station is a shelf or the like, but the location of the cargo handling station is not particularly limited as long as it is a location where a forklift transfers cargo. Further, the characteristic object 30 may be a stationary object or the like provided in advance for position estimation, instead of the column or wall of the shelf.

Further, in the above-described embodiment, the location requiring accuracy for which position estimation accuracy is required is before the destination point 3B, which is the cargo handling station where cargo is handled by the cargo handling device 2a. It may be an intersection or the like where it is necessary to stop the vehicle.

In the above-described embodiment, the moving body 2 is made to travel along the virtual guide line 3 that is virtually set on the data. It may be a system in which the moving body 2 travels along the magnetic guide lines provided. In this case, as an accuracy-required place where position estimation accuracy is required, for example, at a place where the virtual guide line in front of the cargo handling station is switched to the magnetic guide line, the laser sensor 9 is used to detect the magnetic guide line with high accuracy. The position estimation calculation of the moving body 2 is performed by shortening the use distance range of the detection data.

In the above embodiment, the position estimation unit 6 estimates the position of the moving body 2 using the SLAM technique using laser as the self-position estimation technique, but the present invention is not particularly limited to the SLAM technique. Any technique that estimates the position of the moving body 2 based on detection data from a sensor that detects distance using a laser can be applied.

Further, the traveling control device of the above-described embodiment is a device for automatically traveling a forklift as the mobile body 2 along the traveling route, but the present invention is applicable to all mobile bodies that can automatically travel, such as a carriage. applicable to

2... Mobile body 2a... Cargo handling device 3... Virtual guide line (travel route) 3B... Destination point (cargo handling station) 4... Travel control device 6... Position estimation unit 9... Laser sensor (distance detector) , 10... SLAM controller (estimation calculation unit), 11... Travel motor (drive unit), 12... Steering motor (drive unit), 14... Deviation amount calculation unit (control unit), 15... Use distance change determination unit (determination unit ), 16 drive control section (control section), 30 feature (object), P normal range, Q short range.

Claims (2)

In a travel control device that automatically travels a mobile object along a travel route to a destination point ,
a position estimation unit that estimates the position of the moving object;
a control unit that controls a driving unit of the moving body so as to cause the moving body to travel along the travel route based on the position of the moving body estimated by the position estimation unit ;
a judgment unit that judges whether the mobile body travels in a pre-specified location requiring accuracy in which position estimation accuracy is required, based on the position of the mobile body estimated by the position estimation unit;
The position estimation unit comprises:
a laser sensor that detects a distance to an object around the moving body by irradiating a laser around the moving body and receiving reflected light of the laser;
an estimation calculation unit that performs an estimation calculation of the position of the moving object based on the detection data of the laser sensor ;
The location requiring accuracy is a location in front of the destination point or a location where the moving body needs to be stopped;
When the moving object travels in the location requiring accuracy, the laser sensor emits light closer to the moving object along the traveling route than when the moving object travels in a location other than the location requiring accuracy. There is a feature that is a stationary object that reflects the laser that causes
The estimation calculation unit is configured such that when the determination unit determines that the mobile body travels in the location requiring accuracy, the amount of the moving object is higher than when the determination unit determines that the mobile object travels in a location other than the location requiring accuracy. and a running control device for estimating the position of the moving body by shortening the usable distance range so that the characteristic object is arranged within the usable distance range of the detection data of the laser sensor . The moving body has a cargo handling device that performs cargo handling work,
2. A travel control system according to claim 1, wherein said location requiring accuracy is in front of a cargo handling station where cargo is handled by said cargo handling device.

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